doctordun is talking about an UPGRADE to CS6. The licensing system for CS6 is different than for previous versions, as will be made clear in the forthcoming announcement, however the upgrade rule remains:

"Once I've upgraded, can I use, sell, or transfer the previous versions of the software?

No. Purchasing an upgrade to your product extends your existing license to cover the new version of Adobe software. It does not provide you with two separate licenses for the old version and the new version" [FAQ]

The licensing system for CS6 is different than for previous versions, as will be made clear in the forthcoming announcement,

I'll await the changes in CS6 with interest.

I know about the forthcoming change to one-version-back for upgrades but I'm not aware of any EULA changes yet.

"Once I've upgraded, can I use, sell, or transfer the previous versions of the software?

No. Purchasing an upgrade to your product extends your existing license to cover the new version of Adobe software. It does not provide you with two separate licenses for the old version and the new version" [FAQ]

If the Software is an Update to a prior version of Adobe software (the "Prior Version"), the following apply:

Your use of this Update is conditional upon your retention of the Prior Version. Therefore, if you validly transfer this Update pursuant to Section 4.6, you must transfer the Prior Verision along with it. If you wish to use this Update in addition to the Prior Version, you may only do so on the same Computer on which you have installed and are using the Prior Version...."

If this wording remains unchanged for the CS6 EULA, that tells me that it's OK to have CS5.5 and the CS6 upgrade installed on two computers and use both CS5.5 and CS6 on each computer.

I do so daily with CS4 and CS5.

Given the above from the EULA, it seems that the FAQ should remove the word "use" from the question.